Deep medullary vein involvement in neonates with brain damage: an MR imaging study

Cerebral venous thrombosis and deep medullary vein thrombosis: Padua experience over the last two decades

BACKGROUND

Cerebral venous thrombosis (CVT) is a cerebrovascular disorder that accounts for 20% of perinatal strokes. CVT incidence ranges from 0.67 to 1.12 per 100,000 newborns, while the incidence of "deep medullary vein thrombosis" (DMVT), a subtype of CVT, cannot be accurately estimated. This study aims to analyze the case history of CVT in the neonatal period, with a specific focus on DMVT.

MATERIALS AND METHODS

Newborns diagnosed with CVT, with or without DMVT, between January 2002 and April 2023, were collected using the Italian Registry of Infantile Thrombosis (RITI). Cerebral MRIs were reviewed by an expert neuroradiologist following a standardized protocol.

RESULTS

Forty-two newborns with CVT were identified, of which 27/42 (64%) had CVT, and the remaining 15/42 (36%) had DMVT (isolated DMVT in 9/15). Symptom onset occurred in the first week of life (median 8 days, IQR 4-14) with a male prevalence of 59%. The most common risk factors for CVT were complicated delivery (38%), prematurity (40%), congenital heart diseases (48%), and infections (40%). Seizures were the predominant presenting symptom in 52% of all cases. Hemorrhagic infarction was higher in cases with isolated DMVT (77%) compared to patients with CVT without DMVT (p = 0.013). Antithrombotic treatment was initiated in 36% of patients. Neurological impairment was observed in 48% of cases at discharge, while 18 out of 31 infants (58%) presented one or more neurological deficits at long term follow up.     Conclusion: DMVT occurs in over a third of neonates with CVT. Multicentric studies are essential to establish standardized protocols for therapy, neuroimaging, and follow-up in these patients.

Evaluation of Neonatal Cerebral Circulation Under Hypoxic Ischemic Risk Factors Based on Quantitative Analysis of Cerebral Veins with Magnetic Resonance Susceptibility Weighted Imaging

PURPOSE

To observe the regulation of cerebral circulation in vivo based on image segmentation algorithms for deep learning in medical imaging to automatically detect and quantify the neonatal deep medullary veins (DMVs) on susceptibility weighted imaging (SWI) images. To evaluate early cerebral circulation self-rescue for neonates undergoing risk of cerebral hypoxia-ischaemia in vivo.

METHODS

SWI images and clinical data of 317 neonates with or without risk of cerebral hypoxia-ischaemia were analyzed. Quantitative parameters showing the number, width, and curvature of DMVs were obtained using an image segmentation algorithm.

RESULTS

The number of DMVs was greater in males than in females (p < 0.01), and in term than in preterm infants (p = 0.001). The width of DMVs was greater in term than in preterm infants (p < 0.01), in low-risk than in high-risk group (p < 0.01), and in neonates without intracranial extracerebral haemorrhage (ICECH) than with ICECH (p < 0.05). The curvature of DMVs was greater in term than in preterm infants (P < 0.05). The width of both bilateral thalamic veins and anterior caudate nucleus veins were positively correlated with the number of DMVs; the width of bilateral thalamic veins was positively correlated with the width of DMVs.

CONCLUSION

The DMVs quantification based on image segmentation algorithm may provide more detailed and stable quantitative information in neonate. SWI vein quantification may be an observable indicator for in vivo assessment of cerebral circulation self-regulation in neonatal hypoxic-ischemic brain injury.

Neonatal cerebral ultrasound: anatomical variants and age-related diseases

Cerebral ultrasound is a non-invasive imaging technique widely used for the assessment of brain anatomy and diseases in neonates and infants. Indeed, it allows a precise characterization of common variants such as cavum septum pellucidum or diseases like intraventricular hemorrhage. The aim of this pictorial review is to provide a comprehensive overview of the main ultrasound features of the most common cerebral anatomical variants and disorders detectable by cerebral ultrasound using an age-related approach which could support non-subspecialized radiologists.

Neuroimaging of Neonatal Stroke: Venous Focus

Perinatal venous infarcts are underrecognized clinically and at imaging. Neonates may be susceptible to venous infarcts because of hypercoagulable state, compressibility of the dural sinuses and superficial veins due to patent sutures, immature cerebral venous drainage pathways, and drastic physiologic changes of the brain circulation in the perinatal period. About 43% of cases of pediatric cerebral sinovenous thrombosis occur in the neonatal period. Venous infarcts can be recognized by ischemia or hemorrhage that does not respect an arterial territory. Knowledge of venous drainage pathways and territories can help radiologists recognize characteristic venous infarct patterns. Intraventricular hemorrhage in a term neonate with thalamocaudate hemorrhage should raise concern for internal cerebral vein thrombosis. A striato-hippocampal pattern of hemorrhage indicates basal vein of Rosenthal thrombosis. Choroid plexus hemorrhage may be due to obstruction of choroidal veins that drain the internal cerebral vein or basal vein of Rosenthal. Fan-shaped deep medullary venous congestion or thrombosis is due to impaired venous drainage into the subependymal veins, most commonly caused by germinal matrix hemorrhage in the premature infant and impeded flow in the deep venous system in the term infant. Subpial hemorrhage, an underrecognized hemorrhage stroke type, is often observed in the superficial temporal region, and its cause is probably multifactorial. The treatment of cerebral sinovenous thrombosis is anticoagulation, which should be considered even in the presence of intracranial hemorrhage. ©RSNA, 2024 Test Your Knowledge questions in the supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article.

Perinatal hypoxic-ischemic brain injury: What's behind the "ribbon effect"?

Ribbon effect describes a perceived macroscopic color reversal of the gray and white matter, characterized by a pale cortex and diffusely dusky underlying white matter. This finding is thought to be unique to the perinatal period and indicative of hypoxic-ischemic injury. However, the clinical and microscopic correlates of this macroscopic finding have not been clearly defined. A 21-year retrospective study of autopsies was performed. Ribbon effect was seen in 190 subjects, ages 20 weeks gestation to 9.5 months adjusted age. Clinical associations and radiographic findings were similar in ribbon effect cases and controls. A variety of histologic findings were observed including acute neuronal injury, diffuse white matter gliosis, and white matter necrosis. Only white matter vascular congestion was significantly correlated to the macroscopic severity of ribbon effect; the severity of white matter injury and acute neuronal injury were not significantly correlated to ribbon effect. While hypoxic-ischemic changes were present in nearly all cases of ribbon effect, the location, severity, and chronicity of these changes varied considerably, and similar findings were observed in controls. The presence of ribbon effect therefore does not predict microscopic findings apart from vascular congestion, highlighting the importance of microscopic examination in perinatal brain autopsies.

Deep Medullary Vein Thrombosis in Newborns: A Systematic Literature Review

BACKGROUND

Deep medullary vein (DMV) thrombosis is a rare cause of brain damage in both preterm and full-term neonates. In this study, we aimed to collect data on clinical and radiological presentation, treatment, and outcome of neonatal DMV thrombosis.

METHODS

Systematic literature review on neonatal DMV thrombosis was carried out in PubMed, ClinicalTrial.gov, Scopus, and Web of Science up to December 2022.

RESULTS

Seventy-five published cases of DMV thrombosis were identified and analysed (preterm newborns were 46%). Neonatal distress, respiratory resuscitation, or need for inotropes were present in 34/75 (45%) of patients. Signs and symptoms at presentation included seizures (38/75, 48%), apnoea (27/75, 36%), lethargy or irritability (26/75, 35%). At magnetic resonance imaging (MRI), fan-shaped linear T2 hypointense lesions were documented in all cases. All had ischaemic injuries, most often involving the frontal (62/74, 84%) and parietal lobes (56/74, 76%). Signs of haemorrhagic infarction were present in 53/54 (98%). Antithrombotic treatment was not mentioned in any of the studies included. Although mortality was low (2/75, 2.6%), a large proportion of patients developed neurological sequelae (intellectual disability in 19/51 [37%] and epilepsy in 9/51 [18%] cases).

CONCLUSIONS

DMV thrombosis is rarely identified in the literature, even if it is possibly under-recognized or under-reported. Presentation in neonatal age is with seizures and non-specific systemic signs/symptoms that often cause diagnostic delay, despite the pathognomonic MRI picture. The high rate of morbidity, which determines significant social and health costs, requires further in-depth studies aimed at earlier diagnosis and evidence-based prevention and therapeutic strategies.

A radiomics-based study of deep medullary veins in infants: Evaluation of neonatal brain injury with hypoxic-ischemic encephalopathy via susceptibility-weighted imaging

Objective

The deep medullary veins (DMVs) can be evaluated using susceptibility-weighted imaging (SWI). This study aimed to apply radiomic analysis of the DMVs to evaluate brain injury in neonatal patients with hypoxic-ischemic encephalopathy (HIE) using SWI.

Methods

This study included brain magnetic resonance imaging of 190 infants with HIE and 89 controls. All neonates were born at full-term (37+ weeks gestation). To include the DMVs in the regions of interest, manual drawings were performed. A Rad-score was constructed using least absolute shrinkage and selection operator (LASSO) regression to identify the optimal radiomic features. Nomograms were constructed by combining the Rad-score with a clinically independent factor. Receiver operating characteristic curve analysis was applied to evaluate the performance of the different models. Clinical utility was evaluated using a decision curve analysis.

Results

The combined nomogram model incorporating the Rad-score and clinical independent predictors, was better in predicting HIE (in the training cohort, the area under the curve was 0.97, and in the validation cohort, it was 0.95) and the neurologic outcomes after hypoxic-ischemic (in the training cohort, the area under the curve was 0.91, and in the validation cohort, it was 0.88).

Conclusion

Based on radiomic signatures and clinical indicators, we developed a combined nomogram model for evaluating neonatal brain injury associated with perinatal asphyxia.

Radiomics based of deep medullary veins on susceptibility-weighted imaging in infants: predicting the severity of brain injury of neonates with perinatal asphyxia

OBJECTIVE

This study aimed to apply radiomics analysis of the change of deep medullary veins (DMV) on susceptibility-weighted imaging (SWI), and to distinguish mild hypoxic-ischemic encephalopathy (HIE) from moderate-to-severe HIE in neonates.

METHODS

A total of 190 neonates with HIE (24 mild HIE and 166 moderate-to-severe HIE) were included in this study. All of them were born at 37 gestational weeks or later. The DMVs were manually included in the regions of interest (ROI). For the purpose of identifying optimal radiomics features and to construct Rad-scores, 1316 features were extracted. LASSO regression was used to identify the optimal radiomics features. Using the Red-score and the clinical independent factor, a nomogram was constructed. In order to evaluate the performance of the different models, receiver operating characteristic (ROC) curve analysis was applied. Decision curve analysis (DCA) was implemented to evaluate the clinical utility.

RESULTS

A total of 15 potential predictors were selected and contributed to Red-score construction. Compared with the radiomics model, the nomogram combined model incorporating Red-score and urea nitrogen did not better distinguish between the mild HIE and moderate-to-severe HIE group. For the training cohort, the AUC of the radiomics model and the combined nomogram model was 0.84 and 0.84. For the validation cohort, the AUC of the radiomics model and the combined nomogram model was 0.80 and 0.79, respectively. The addition of clinical characteristics to the nomogram failed to distinguish mild HIE from moderate-to-severe HIE group.

CONCLUSION

We developed a radiomics model and combined nomogram model as an indicator to distinguish mild HIE from moderate-to-severe HIE group.

Infection and inflammation: radiological insights into patterns of pediatric immune-mediated CNS injury

The central nervous system (CNS) undergoes constant immune surveillance enabled via regionally specialized mechanisms. These include selectively permissive barriers and modifications to interlinked innate and adaptive immune systems that detect and remove an inciting trigger. The end-points of brain injury and edema from these triggers are varied but often follow recognizable patterns due to shared underlying immune drivers. Imaging provides insights to understanding these patterns that often arise from unique interplays of infection, inflammation and genetics. We review the current updates in our understanding of these intersections and through examples of cases from our practice, highlight that infection and inflammation follow diverse yet convergent mechanisms that can challenge the CNS in children.

Current understanding and future potential applications of cerebral microvascular imaging in infants

Microvascular imaging is an advanced Doppler ultrasound technique that detects slow flow in microvessels by suppressing clutter signal and motion-related artifacts. The technique has been applied in several conditions to assess organ perfusion and lesion characteristics. In this pictorial review, we aim to describe current knowledge of the technique, particularly its diagnostic utility in the infant brain, and expand on the unexplored but promising clinical applications of microvascular imaging in the brain with case illustrations.

Cerebral Venous Sinus Thrombosis in Preterm Infants

BACKGROUND:

Neonatal cerebral venous sinus thrombosis (CVST) can lead to brain injury and neurodevelopmental impairments. Previous studies of neonatal CVST have focused on term infants, and studies of preterm infants are lacking. In this study, we examined the clinical and radiological features, treatment and outcome of CVST in preterm infants.

METHODS:

This was a retrospective, consecutive cohort study of preterm infants (gestational age <37 weeks) with radiologically confirmed CVST. All magnetic resonance imaging/MRV and CT/CTV scans were re-reviewed to study thrombus characteristics and pattern of brain injury. Outcome was assessed by the validated pediatric stroke outcome measure at the most recent clinic visit.

RESULTS:

Twenty-six preterm infants with CVST were studied. Of these, 65% were moderate-late preterm (32–37 weeks), 27% very preterm (28–32 weeks), and 8% extreme preterm (<28 weeks). Most (73%) were symptomatic at presentation with seizures or abnormal exam. Transverse (85%) and superior sagittal (42%) sinuses were common sites of thrombosis. Parenchymal brain injury was predominantly periventricular (35%) and deep white matter (31%) in location. Intraventricular hemorrhage occurred in 46%. Most infants (69%) were treated with anticoagulation. No treated infant (including eleven with pretreatment hemorrhage) had new or worsening post-treatment hemorrhage. Outcomes ranged from no deficits (50%), mild-moderate (25%), and severe (25%) impairment.

CONCLUSIONS:

In our sample of preterm infants with CVST, more than one-quarter were asymptomatic. White matter brain lesions predominated and one-half had neurological deficits at follow-up. Anticoagulation of preterm CVST in this small cohort appeared to be safe. Larger studies of preterm CVST are needed.

Neuroradiological Mimics of Periventricular Leukomalacia

AIM

Periventricular leukomalacia (PVL) is a term reserved to describe white matter injury in the premature brain. In this review article, the authors highlight the common and rare pathologies mimicking the chronic stage of PVL and propose practical clinico-radiological criteria that would aid in diagnosis and management.

METHODS AND RESULTS

The authors first describe the typical brain MRI (magnetic resonance imaging) features of PVL. Based on their clinical presentation, pathologic entities and their neuroimaging findings were clustered into distinct categories. Three clinical subgroups were identified: healthy children, children with stable/nonprogressive neurological disorder, and those with progressive neurological disorder. The neuroradiological discriminators are described in each subgroup with relevant differential diagnoses. The mimics were broadly classified into normal variants, acquired, and inherited disorders.

CONCLUSIONS

The term "PVL" should be used appropriately as it reflects its pathomechanism. The phrase "white matter injury of prematurity" or "brain injury of prematurity" is more specific. Discrepancies in imaging and clinical presentation must be tread with caution and warrant further investigations to exclude other possibilities.

A 10-Year Retrospective Review of Prenatal Applications, Current Challenges and Future Prospects of Three-Dimensional Sonoangiography

Realistic reconstruction of angioarchitecture within the morphological landmark with three-dimensional sonoangiography (three-dimensional power Doppler; 3D PD) may augment standard prenatal ultrasound and Doppler assessments. This study aimed to (a) present a technical overview, (b) determine additional advantages, (c) identify current challenges, and (d) predict trajectories of 3D PD for prenatal assessments. PubMed and Scopus databases for the last decade were searched. Although 307 publications addressed our objectives, their heterogeneity was too broad for statistical analyses. Important findings are therefore presented in descriptive format and supplemented with the authors’ 3D PD images. Acquisition, analysis, and display techniques need to be personalized to improve the quality of flow-volume data. While 3D PD indices of the first-trimester placenta may improve the prediction of preeclampsia, research is needed to standardize the measurement protocol. In highly experienced hands, the unique 3D PD findings improve the diagnostic accuracy of placenta accreta spectrum. A lack of quality assurance is the central challenge to incorporating 3D PD in prenatal care. Machine learning may broaden clinical translations of prenatal 3D PD. Due to its operator dependency, 3D PD has low reproducibility. Until standardization and quality assurance protocols are established, its use as a stand-alone clinical or research tool cannot be recommended.

Deep medullary vein engorgement and superficial medullary vein engorgement: two patterns of perinatal venous stroke

Perinatal venous stroke has classically been attributed to cerebral sinovenous thrombosis with resultant congestion or thrombosis of the small veins draining the cerebrum. Advances in brain MRI, in particular susceptibility-weighted imaging, have enabled the visualization of the engorged small intracerebral veins, and the spectrum of perinatal venous stroke has expanded to include isolated congestion or thrombosis of the deep medullary veins and the superficial intracerebral veins. Congestion or thrombosis of the deep medullary veins or the superficial intracerebral veins can result in vasogenic edema, cytotoxic edema or hemorrhage in the territory of disrupted venous flow. Deep medullary vein engorgement and superficial medullary vein engorgement have characteristic findings on MRI and should be differentiated from neonatal hemorrhagic stroke.

Nosological Differences in the Nature of Punctate White Matter Lesions in Preterm Infants

Background: The pathogenesis of punctuate white matter lesions (PWMLs), a mild form of white matter damage observed in preterm infants, is still a matter of debate. Susceptibility-weighted imaging (SWI) allows to differentiate PWMLs based on the presence (SWI+) or absence (SWI-) of hemosiderin, but little is known about the significance of this distinction. This retrospective study aimed to compare neuroradiological and clinical characteristics of SWI+ and SWI- PWMLs. Materials and Methods: MR images of all VLBW infants scanned consecutively at term-equivalent age between April 2012 and May 2018 were retrospectively reviewed, and infants with PWMLs defined as small areas of high T1 and/or low T2 signal in the periventricular white matter were selected and included in the study. Each lesion was analyzed separately and characterized by localization, organization pattern, and distance from the lateral ventricle. Clinical data were retrieved from the department database. Results: A total of 517 PWMLs were registered in 81 patients, with 93 lesions (18%) visible on SWI (SWI+), revealing the presence of hemosiderin deposits. On univariate analysis, compared to SWI- PWML, SWI+ lesions were closer to the ventricle wall, more frequently organized in linear pattern and associated with lower birth weight, lower gestational age, lower admission temperature, need for intubation, bronchopulmonary dysplasia, retinopathy of prematurity, and presence of GMH-IVH. On multivariate analysis, closer distance to the ventricle wall on axial scan and lower birth weight were associated with visibility of PMWLs on SWI (p = 0.003 and p = 0.0001, respectively). Conclusions: Our results suggest a nosological difference between SWI+ and SWI- PWMLs. Other prospective studies are warranted to corroborate these observations.

Deep Medullary Vein White Matter Injury Global Severity Score Predicts Neurodevelopmental Impairment

AIM

To examine associations between the deep medullary vein white matter injury global severity scoring system and neurodevelopmental impairment.

METHODS

This is a prospective observational cohort study of infants born at ≥32 weeks, diagnosed with deep medullary vein thrombosis and infarction on neuroimaging in the first month of life. Developmental testing was performed using validated measures for early, preschool, and school-age follow-up.

RESULTS

Nineteen (37%) patients had major neurodevelopmental impairment. Global severity score was higher among patients with neurodevelopmental impairment (21.6 vs 13.4, P = .04). Overall, 78% of patients with epilepsy had neurodevelopmental impairment. A greater degree of asymmetry with right-sided injury predominance was associated with lower Bayley-III cognitive scores and presence of neurodevelopmental impairment (P < .01).

CONCLUSIONS

Results suggest a need for targeted clinical surveillance for patients with a high global severity score and/or asymmetric, predominantly right cerebral white matter injury and for those who develop epilepsy.

Cerebral Venous Thrombosis Associated with COVID-19

Despite the severity of coronavirus disease 2019 (COVID-19) being more frequently related to acute respiratory distress syndrome and acute cardiac and renal injuries, thromboembolic events have been increasingly reported. We report a unique series of young patients with COVID-19 presenting with cerebral venous system thrombosis. Three patients younger than 41 years of age with confirmed Severe Acute Respiratory Syndrome coronavirus 2 (SARS-Cov-2) infection had neurologic findings related to cerebral venous thrombosis. They were admitted during the short period of 10 days between March and April 2020 and were managed in an academic institution in a large city. One patient had thrombosis in both the superficial and deep systems; another had involvement of the straight sinus, vein of Galen, and internal cerebral veins; and a third patient had thrombosis of the deep medullary veins. Two patients presented with hemorrhagic venous infarcts. The median time from COVID-19 symptoms to a thrombotic event was 7 days (range, 2-7 days). One patient was diagnosed with new-onset diabetic ketoacidosis, and another one used oral contraceptive pills. Two patients were managed with both hydroxychloroquine and azithromycin; one was treated with lopinavir-ritonavir. All patients had a fatal outcome. Severe and potentially fatal deep cerebral thrombosis may complicate the initial clinical presentation of COVID-19. We urge awareness of this atypical manifestation.

Neonatal Neuroimaging

Significant advances in the field of neonatal imaging has resulted in the generation of large complex data sets of relevant information for routine daily clinical practice, and basic and translational research. The evaluation of this data is a complex task for the neonatal imager who must distinguish normal and incidental findings from clinically significant abnormalities which are often adjunctive data points applicable to clinical evaluation and treatment. This review provides an overview of the imaging manifestations of disease processes commonly encountered in the neonatal brain. Since MRI is currently the highest yield technique for the diagnosis and characterization of the normal and abnormal brain, it is therefore the focus of the majority of this review. When applicable, discussion of some of the pertinent known pathophysiology and neuropathological aspects of disease processes are reviewed.

Isolated superior striate vein thrombosis in adults

BACKGROUND

Isolated cerebral deep medullary vein thrombosis has been described in the setting of hemorrhagic periventricular white matter lesions in preterm and full-term neonates, but to the best of our knowledge, has never been reported in adults. We present two cases of isolated thrombosis of the superior striate vein occurring in adults that could be analogous to deep medullary vein thrombosis in that they involve deep cerebral veins only without thrombosis of the subependymal or internal cerebral veins.

CASE DESCRIPTION

Two women aged 20 and 39, presented with transient neurological deficits and headache. Diagnosis of isolated superior striate vein thrombosis was based on CT and MRI findings with long term imaging follow-up. Both patients evolved favorably under conservative treatment without anticoagulation. Thrombophilia workup was negative and both patients were active smokers under oral contraception.

CONCLUSION

Isolated superior striate vein thrombosis is a rare form of intracranial venous thrombosis and should be considered in the differential diagnosis of stroke-like episodes with headache in adults. Isolated superior striate vein thrombosis presents with characteristic imaging features on CT and MRI.

An Important Finding of White Matter Injury in Late Preterm Infant: Deep Medullary Vein Involvement

Objective: To investigate high risk factors and magnetic resonance imaging (MRI) features in late preterm infants with severe white matter injury (WMI) associated with abnormal deep medullary veins (DMVs). Materials and Methods: Preterm infants with severe WMI, who were hospitalized in Shengjing Hospital from 1st January 2009 to 31st December 2018, were enrolled in this retrospective study. High risk factors and MRI characteristics of infants with abnormal DMVs were analyzed and compared with those of infants without DMV abnormalities. Results: A total of 2032 late preterm infants were examined by MRI; 71 cases (3.5%) had severe WMI and 15 of these (21.1%) had abnormal DMVs. The incidence of maternal diabetes was higher in infants with abnormal DMVs and neonatal convulsions were more likely (P < 0.05). The incidence of grade IV injury (P < 0.05), white matter periventricular cysts and thalamic injury (P < 0.01), cerebral venous sinus thrombus (P < 0.01) and germinal matrix/intraventricular hemorrhage (P < 0.05) were higher in infants with abnormal DMVs than in infants with normal DMVs. Conclusions: Congestion/thrombosis of DMVs may be an important cause of severe WMI in late preterm infants, especially in periventricular leukomalacia-like WMI. WMI with abnormal DMVs is more likely to lead to thalamic injury.

Venous pathologies in paediatric neuroradiology: from foetal to adolescent life

The interpretation of cerebral venous pathologies in paediatric practice is challenging as there are several normal anatomical variants, and the pathologies are diverse, involving the venous system through direct and indirect mechanisms. This paper aims to provide a comprehensive review of these entities, as their awareness can avoid potential diagnostic pitfalls. We also propose a practical classification system of paediatric cerebral venous pathologies, which will enable more accurate reporting of the neuroimaging findings, as relevant to the underlying pathogenesis of these conditions. The proposed classification system comprises of the following main groups: arterio-venous shunting-related disorders, primary venous malformations and veno-occlusive disorders. A multimodal imaging approach has been included in the relevant subsections, with a brief overview of the modality-specific pitfalls that can also limit interpretation of the neuroimaging. The article also summarises the current literature and international practices in terms of management options and outcomes in specific disease entities.

Punctate white matter lesions of preterm infants: Risk factor analysis

AIM

Punctate white matter lesions (PWML) are frequently detected in preterm infants undergoing brain MRI at term equivalent age (TEA). The aims of this study were to assess prevalence of PWML and to identify risk factors for PWML in VLBW infants.

METHODS

Brain MRI scans obtained at TEA and clinical charts of a consecutive sample of very low birth weight (VLBW) infants admitted to Gaslini Children's Hospital NICU between 2012 and 2016 were retrospectively analyzed. MRI protocol included Susceptibility Weighted Imaging (SWI) sequence in order to identify hemosiderin depositions as a result of previous microbleeds. PWML were classified according to their number (≤6 lesions and >6 lesions) and signal characteristics (SWI+ lesions and SWI- lesions). Univariate and multivariable analysis were performed in order to identify risk factors for PWML (as a whole) and for each subgroup of PWML.

RESULTS

321 VLBW infants were included. PWML were identified in 61 subjects (19%), 26 of whom (8% of the study population) had more than 6 lesions. Risk factors for PWML (as a whole) were higher birth weight (OR = 1.001; p = 0.04) and absent or incomplete antenatal steroid course (OR = 2.13; p = 0.02). Risk factors for >6 PWML were need for intubation (OR = 11.9; p = 0.003) and higher Apgar score at 5 min (OR = 1.8; p = 0.02). Presence of GMH-IVH was the only identified risk factor for SWI + lesions.

CONCLUSIONS

Our results confirm the high prevalence of PWML among VLBW infants. Differentiation between SWI+ and SWI- lesions is crucial as they have different risk factors and may likely represent two different entities.

MR Imaging Scoring System for White Matter Injury after Deep Medullary Vein Thrombosis and Infarction in Neonates

BACKGROUND AND PURPOSE

Advanced imaging techniques have allowed earlier and more accurate detection of cerebral deep medullary vein thrombosis and infarction. Our objective was to develop an MR imaging scoring system to evaluate the severity of white matter injury in neonates with deep medullary vein thrombosis and infarction.

MATERIALS AND METHODS

This was a retrospective study of infants born ≥32 weeks' gestation (2000-2016) diagnosed with deep medullary vein thrombosis and infarction on neuroimaging in the first 30 days of life. A 102-point deep medullary vein white matter injury global severity score was developed. MR images were scored by 2 pediatric radiologists. Subject clinical data and regional and global severity scores were recorded.

RESULTS

Fifty-one patients (mean gestational age, 37.3 ± 2.2 weeks; mean birth weight, 3182 ± 720 g) were included with a mean age at diagnosis via MR imaging of postnatal day 10.1 ± 6.1. Global severity scores ranged from 1 to 53, with a median score of 11 (interquartile range, 5-25). Lesions were more common in the frontal and parietal regions and less common in the occipital and temporal regions. Fifty-five percent of the group had neonatal seizures. No difference in perinatal risk factors (gestational age, birthweight, 5-minute Apgar score, chorioamnionitis, delivery room resuscitation, ventilator, or inotrope requirement) was observed among severity score quartiles.

CONCLUSIONS

An MR imaging scoring system provides a comprehensive and objective classification of WM injury after deep medullary vein thrombosis and infarction in late preterm and term neonates. The global severity score is independent of gestational age and other antenatal risk factors, consistent with presentation in previously healthy-appearing neonates.

Imaging patterns of venous-related brain injury in children

Venous-related brain injury is a common form of cerebrovascular injury in children and encompasses a diverse group of cerebrovascular diagnoses. The purpose of this pictorial essay is to introduce the relevant anatomy, pathophysiology and various imaging patterns of venous-related cerebral injury in children. Unifying concepts to better understand the effects of venous hypertension in the developing brain will be emphasized. These unifying concepts will provide the imaging professional with a conceptual framework to better understand and confidently identify imaging patterns of venous-related cerebral injury.

Structure of the Medullary Veins of the Cerebral Hemisphere and Related Disorders

Deep medullary veins drain into subependymal veins with four convergence zones and show parallel distribution patterns adjacent to the body or inferior horn and a radial pattern in the frontal horn or trigon of the lateral ventricle. As white matter imaging develops such as diffusion tensor imaging or susceptibility-weighted imaging, requirements for understanding of white matter structures are increasing, not only for understanding of neuronal tracts but also for that of other structures including the fine anatomy of white matter vessels. Some disorders are related to deep medullary veins and show characteristic distributions of the lesions indicating the relationship to the medullary veins. When lesions show a parallel or radial distribution pattern in the certebral deep white matter, disorders related to deep medullary veins should be considered for differential diagnosis. In this review, we discuss disorders related to deep medullary veins, including (a) anomalies of the medullary veins, (b) hemorrhagic disorders related to the medullary veins (diffuse vascular injury due to high-energy trauma, deep medullary vein engorgement/thrombosis in neonates), (c) inflammatory changes that spread along the medullary veins, (d) neoplasms within the medullary veins, and (e) metabolic changes that lead to altered visualization of medullary veins. Understanding the anatomic structure of medullary veins in the cerebral hemisphere and becoming familiar with disorders in which the medullary veins play a major role in disease development may be helpful in the interpretation of brain images. ^©RSNA, 2017.

MAVEN: An Algorithm for Multi-Parametric Automated Segmentation of Brain Veins From Gradient Echo Acquisitions

Cerebral vein analysis provides a chance to study, from an unusual viewpoint, an entire class of brain diseases, including neurodegenerative disorders and traumatic brain injuries. Manual segmentation approaches can be used to assess vascular anatomy, but they are observer-dependent and time-consuming; therefore, automated approaches are desirable, as they also improve reproducibility. In this paper, a new, fully automated algorithm, based on structural, morphological, and relaxometric information, is proposed to segment the entire cerebral venous system from MR images. The algorithm for multi-parametric automated segmentation of brain VEiNs (MAVEN) is based on a combined investigation of multi-parametric information that allows for rejection of false positives and detection of thin vessels. The method is tested on gradient echo brain data sets acquired at 1.5, 3, and 7 T. It is compared to previous methods against manual segmentation, and its inter-scan reproducibility is assessed. The achieved accuracy and reproducibility are good, meaning that MAVEN outperforms previous methods on both quantitative and qualitative analyses. It is usable at all the field strengths explored, showing comparable accuracy scores, with no need for algorithm parameter adjustments, and thus, it is a promising candidate for the characterization of the venous tree topology.

Isolated Cystic Periventricular Leukomalacia Differs from Cystic Periventricular Leukomalacia with Intraventricular Hemorrhage in Prevalence, Risk Factors and Outcomes in Preterm Infants

BACKGROUND

Cystic periventricular leukomalacia (cPVL) is the most severe white matter injury and is often associated with intraventricular hemorrhage (IVH) in preterm infants.

OBJECTIVE

The aim of this study was to investigate the prevalence, risk factors and neurodevelopmental outcomes of isolated cPVL and cPVL with low-grade and high-grade IVH in premature infants.

METHODS

From 2001 to 2012, 9,964 infants with <31 weeks' gestational age (GA) admitted to Taiwan hospitals were enrolled. cPVL was classified into three groups: isolated cPVL, cPVL with low-grade (I/II) IVH, and cPVL with high-grade (III) IVH.

RESULTS

Of 7,805 infants with complete ultrasound data, 286 (3.7%) had cPVL. Among the cPVL infants, 93 (32.5%) were isolated, 118 (41.3%) had low-grade IVH and 75 (26.2%) had high-grade IVH. The risk of cPVL with IVH was significantly higher among infants with <27 weeks' GA than those with ≥27 weeks' GA, in contrast to that of isolated cPVL. Using infants without cPVL and IVH as the reference group, the most significant predictor of isolated cPVL was neonatal sepsis (odds ratio 2.39; 95% confidence interval 1.52-3.77), while 5-min Apgar score <5 (2.50; 1.48-4.21) and prolonged mechanical ventilation (2.19; 1.42-3.42) were associated with cPVL with low-grade IVH, and GA <27 weeks (2.63; 1.56-4.42), pneumothorax (3.04; 1.40-6.65) and prolonged mechanical ventilation (3.36; 1.88-6.01) contributed to cPVL with high-grade IVH. cPVL infants with low-grade and high-grade IVH had a higher risk of abnormal neurodevelopmental outcomes than infants with isolated cPVL at the age of 24 months.

CONCLUSIONS

Isolated cPVL, cPVL with low-grade IVH and cPVL with high-grade IVH had different risk factors and neurodevelopmental outcomes, suggestive of different causal pathways.

Radiological and clinical features of cerebral sinovenous thrombosis in newborns and older children

BACKGROUND AND PURPOSE

Cerebral sinovenous thrombosis (CSVT) represents an increasingly recognized cause of pediatric stroke. Our purpose was to assess gender and age differences in the etiology, clinical presentation, and imaging features of CSVT in neonates and older children.

METHODS

Subjects aged newborn to 18 years diagnosed with CSVT at the Lille university hospital between 2011 and 2014 were included.

RESULTS

Eleven neonates and 16 non-neonates constituted the study population. The incidence of CSVT was significantly higher in male newborns. Clinical presentation did not vary significantly between the groups. Risk factors were age-dependent, with acute systemic illnesses significantly predominating in neonates (54%), whereas local infections, prothrombotic conditions, and trauma were more common in older children (36, 27, and 27% respectively). No predisposing factor could be identified in 36% of the neonates as compared to less than 5% of the non-neonates. Thrombosis of the deep venous structures was documented in 73% of the neonates whereas involvement of the superficial sinuses was significantly more frequent in the non-neonates group. Venous infarctions and extraparenchymal hemorrhages were significantly more frequent in the neonates group.

CONCLUSION

Male patients are at higher risk for CSVT than females. In neonates, involvement of the deep venous structures is significantly more common. Brain parenchymal and extraparenchymal changes occur more frequently in this age group than in older children.

Prognostic value of diffusion-weighted imaging summation scores or apparent diffusion coefficient maps in newborns with hypoxic-ischemic encephalopathy

BACKGROUND

The diagnostic and prognostic assessment of newborn infants with hypoxic-ischemic encephalopathy (HIE) comprises, among other tools, diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) maps.

OBJECTIVE

To compare the ability of DWI and ADC maps in newborns with HIE to predict the neurodevelopmental outcome at 2 years of age.

MATERIALS AND METHODS

Thirty-four term newborns with HIE admitted to the Neonatal Intensive Care Unit of Modena University Hospital from 2004 to 2008 were consecutively enrolled in the study. All newborns received EEG, conventional MRI and DWI within the first week of life. DWI was analyzed by means of summation (S) score and regional ADC measurements. Neurodevelopmental outcome was assessed with a standard 1-4 scale and the Griffiths Mental Developmental Scales - Revised (GMDS-R).

RESULTS

When the outcome was evaluated with a standard 1-4 scale, the DWI S scores showed very high area under the curve (AUC) (0.89) whereas regional ADC measurements in specific subregions had relatively modest predictive value. The lentiform nucleus was the region with the highest AUC (0.78). When GMDS-R were considered, DWI S scores were good to excellent predictors for some GMDS-R subscales. The predictive value of ADC measurements was both region- and subscale-specific. In particular, ADC measurements in some regions (basal ganglia, white matter or rolandic cortex) were excellent predictors for specific GMDS-R with AUCs up to 0.93.

CONCLUSIONS

DWI S scores showed the highest prognostic value for the neurological outcome at 2 years of age. Regional ADC measurements in specific subregions proved to be highly prognostic for specific neurodevelopmental outcomes.

Visualizing cerebral veins in fetal brain using susceptibility-weighted MRI

AIM

To explore the feasibility of two-dimensional (2D) susceptibility-weighted imaging (SWI) in the visualization of cerebral veins in the foetal brain.

MATERIALS AND METHODS

Forty-two pregnant healthy women (gestational age: 19-37 weeks, mean: 28.5 ± 7.1 weeks) underwent SWI examination using a 1.5 T MRI system. Two neurologists independently analysed all magnetic resonance imaging (MRI) studies. The relationship between the veins detected and the gestational age was investigated. The prominence of veins was assessed using a categorical score.

RESULTS

In total, 167 veins were detected by SWI in 29 subjects with a symmetric hemisphere distribution (p > 0.05). An additional vein was detected by SWI biweekly from 24 weeks of gestation. Most veins of Galen and internal cerebral veins on SWI images were prominent, whereas others were faint or moderate.

CONCLUSION

SWI appears to be a feasible method of detecting cerebral veins in the foetal brain.

Different gestational ages and changing vulnerability of the premature brain

In recent decades, there has been a general increase in survival rates of preterm and low birth weight infants, but this overall decrease in perinatal mortality has not been accompanied by a decrease in long-term physical and mental disability. In order to reduce the long-term sequelae of prematurity and to establish preventive measures, it is important to identify risk factors since the main determinant of specific vulnerability to different types of lesions is gestational age. The regional tissue vulnerability at a given gestational age is probably determined by the local metabolic requirements together with specific cell characteristics and their level of maturation. In this article, we discuss the most common neonatal cerebral lesions (cerebellar haemorrhage, germinal matrix intraventricular haemorrhage, periventricular leukomalacia, arterial ischaemic stroke, cerebral vein sinus thrombosis and hypoxic-ischaemic encephalopathy) related to the gestational age-dependent vulnerability of the premature brain.

Acquisition guidelines and quality assessment tools for analyzing neonatal diffusion tensor MRI data

Diffusion tensor imaging is a valuable measure in clinical settings to assess diagnosis and prognosis of neonatal brain development. However, obtaining reliable images is not straightforward because of the tissue characteristics of the neonatal brain and the high likelihood of motion artifacts. In this review, we present guidelines on how to acquire DTI data of the neonatal brain and recommend high-quality data acquisition and processing as an essential means to obtain accurate and robust parametric maps. Sudden head movements are problematic for DTI in neonates, and these may lead to incorrect values. We describe strategies to minimize the corrupting effects both in terms of acquisition (eg, more gradient directions) and postprocessing (eg, tensor estimation methods). In addition, tools are described that can help assess whether a dataset is of sufficient quality for further assessment.